Okay so I recently had some problems with ubuntu software centre where if I opened it from the dashboard it would open up, but only display a white screen. Nothing happened, so if I then clicked the 'x', it would ask me if i would like to force close the non responding software centre.

To get round this I've been opening the software centre via terminal which seems to let it work fine.

But i needed it working normally and after lots of attempts I couldn't figure it out so decided to just un-install and reinstall it.

Un-install worked fine, but now for the reinstall. When i type into terminal

sudo apt-get install software-center

I get this back;

Reading package lists... Done
Building dependency tree
Reading state information... Done
Package software-center is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'software-center' has no installation candidate

Make sure you have the repository link.
From:
Main Menu: System > Administration > Software Sources.
Make sure that the Main repository is selected.
You can get a PPA with:
sudo add-apt-repository ppa:software-store-developers/daily-build
or
sudo add-apt-repository ppa:ubuntuone/nightlies